25 merc. bogged down at all throttle speeds . good idle at times when its warmed up, but when cold it seems it runs out off gas when i put it in gear,..water pump has good stream..replaced all gas lines,pick up in tank, ,prime bulb, water separator, cleaned full filter... could it be the plugs or wires.. or is it definitely a carb issue? thanks.

clean the carb

and replace the plugs.

Have you tried any fuel treatments it could be too much eth.or too much octane or some other contaminate that could be carboning your cylinders and varnishing your carb passages.

I would try seafoam first mixed with 87 octane and if it gets better I would do another treatment.

If nothing changes then I would most likely go look at the carbs then replace the plugs and wires.

Clogged fuel tank vent?....pinched fuel line?

i have the same engine and mine was doing the same thing. i brought it to a mechanic and he fixed the linkages and the timing now it runs awesome.